Perhaps the most immediate and eventual cause of the war was Stalin's approval of North Korea's invasion. After all, the war would not have occurred without a North Korea's initial strike on June 25th, 1950, which also could not have been viable without Stalin's consent. On the contrary to the popular notion, Stalin, however, hadn't always been supportive of the war.
Causes of the Korean Conflict in the early 1950s included the U.S. policy of containing Communism, the invasion of South Korea by USSR, and the backing of the USSR by the Chinese government lead by Mao Zedong.
After World War II, the Soviet Union and the United States had policies that worked to counter each other's influence. When the Communist influence reached Korea, the United States and its allies countered with force to stop the spread of Communism.
Examines the American-Soviet Cold War, The Korean War and evaluates the effects and success of Containment. Describes the primary goal of containment as halting the further spread of communism.